Apple Watch band

You can buy 38mm or the newer 40mm bands, they will fit your Watch Series 3 (38mm) case.

You can match most bands with any Apple Watch Series 3 or newer case of the same size. The 41mm bands work with 38mm and 40mm cases; the 45mm bands work with 42mm and 44mm cases.

The Solo Loop and Braided Solo Loop bands are only compatible with Apple Watch SE and Apple Watch Series 4 or newer. The 40mm and 41mm cases work with band sizes 1–9; the 44mm and 45mm cases works with band sizes 4–12.